Re: old slides

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From:Barry Rittman <> (by way of histonet)
To:histonet <>
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	the fading is generally either an overoxidation of the Hx or the medium
becoming slightly aciidic due to carbon dioxide etc.
If the fading is only at the very edges yu could add some more mountant,
this is the cheapest and quiskest remedy.
I would however, recommend that you remove the coverslips and the old
mountant by soaking in xylene and remount in a neutral or slightly alkaline
mountant such as coverbond. You really do not want to leave for more than a
day or so in xylene as the sections may fade even further, as some xylene
solutions are themselves slightly acidic. Ideally you could seal the edges
with a coverslip ringing compound or gold size.
Once faded the stain cannot be easily reconstituted.
An alternative is to restain the sections. This is possible but has the
added danger that the sections are usually fragile, to a large extent it
depends on the extent of the fading and the value to you of the sections.
If restaining I would strongly suggest using a covering of celloidin to
help keep the section on the slide and to use very weak blueing solutions.

At 03:40 PM 10/20/98 -0500, you wrote:

>Another question for the experts.
>I'm in the process of reviewing a teaching slide set which includes
>some slides which are decades old.  Many of the slides show
>fading of the hematoxylin at the edges, while the eosin staining
>looks normal.  Is this an oxidative change?  Can it be cured?
>Thanks in advance for your experience and comments.
>Hal Hawkins
>UT Medical Branch, Galveston, TX

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